| 1. |
- Cederwall, Bo, et al.
(författare)
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Evidence for a spin-aligned neutron-proton paired phase from the level structure of 92Pd
- 2011
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 469:7328, s. 68-71
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Tidskriftsartikel (refereegranskat)abstract
- Shell structure and magic numbers in atomic nuclei were generally explained by pioneering work(1) that introduced a strong spin-orbit interaction to the nuclear shell model potential. However, knowledge of nuclear forces and the mechanisms governing the structure of nuclei, in particular far from stability, is still incomplete. In nuclei with equal neutron and proton numbers (N = Z), enhanced correlations arise between neutrons and protons (two distinct types of fermions) that occupy orbitals with the same quantum numbers. Such correlations have been predicted to favour an unusual type of nuclear superfluidity, termed isoscalar neutron-proton pairing(2-6), in addition to normal isovector pairing. Despite many experimental efforts, these predictions have not been confirmed. Here we report the experimental observation of excited states in the N = Z = 46 nucleus Pd-92. Gamma rays emitted following the Ni-58(Ar-36,2n)Pd-92 fusion-evaporation reaction were identified using a combination of state-of-the-art high-resolution c-ray, charged-particle and neutron detector systems. Our results reveal evidence for a spin-aligned, isoscalar neutron-proton coupling scheme, different from the previous prediction(2-6). We suggest that this coupling scheme replaces normal superfluidity (characterized by seniority coupling(7,8)) in the ground and low-lying excited states of the heaviest N = Z nuclei. Such strong, isoscalar neutron-proton correlations would have a considerable impact on the nuclear level structure and possibly influence the dynamics of rapid proton capture in stellar nucleosynthesis.
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| 2. |
- Sohler, D., et al.
(författare)
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Yrast states of the proton drip line nucleus 106 Sb
- 1999
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Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993 .- 0556-2813 .- 1089-490X. ; 59:3, s. 1324-1327
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Tidskriftsartikel (refereegranskat)abstract
- Yrast states of [Formula Presented] have been investigated in the [Formula Presented] reaction using in-beam [Formula Presented]-spectroscopic methods and in the [Formula Presented] reaction performing delayed [Formula Presented] and conversion electron studies. A new isomeric state was found at 103 keV with [Formula Presented] The number of states and transitions in the proposed level scheme have been doubled. The experimental results are discussed within the framework of the shell model. © 1999 The American Physical Society.
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| 3. |
- Zheng, Y., et al.
(författare)
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gamma-ray linear polarization measurements and (g(9/2))(-3) neutron alignment in Ru-91
- 2013
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Ingår i: Physical Review C. Nuclear Physics. - : American Physical Society (APS). - 0556-2813 .- 1089-490X. ; 87:4, s. 044328-
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Tidskriftsartikel (refereegranskat)abstract
- Linear polarization measurements have been performed for gamma rays in Ru-91 produced with the Ni-58(Ar-36,2p1n gamma)Ru-91 reaction at a beam energy of 111 MeV. The EXOGAM Ge clover array has been used to measure the gamma-gamma coincidences, gamma-ray linear polarization, and gamma-ray angular distributions. The polarization sensitivity of the EXOGAM clover detectors acting as Compton polarimeters has been determined in the energy range 0.3-1.3 MeV. Several transitions have been observed for the first time. Measurements of linear polarization and angular distribution have led to the firm assignments of spin differences and parity of high-spin states in Ru-91. More specifically, calculations using a semiempirical shell model were performed to understand the structures of the first and second (21/2(+)) and (17/2(+)) levels. The results are in good agreement with the experimental data, supporting the interpretation of the nonyrast (21/2(+)) and (17/2(+)) states in terms of the J(max) and J(max) - 2 members of the seniority-three nu(g(9/2))(-3) multiplet.
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| 4. |
- Lipoglavsek, M, et al.
(författare)
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Stability of Sn-100(50)50 deduced from excited states in Cd-99(48)51 stability of
- 1996
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Ingår i: PHYSICAL REVIEW LETTERS. - : AMER INST PHYSICS. - 0031-9007. ; 76:6, s. 888-891
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Excited states of neutron deficient nuclei close to Sn-100 were investigated in an in-beam spectroscopic experiment using the NORDBALL detector array. Excited states in Cd-99 were identified for the first time. The measured half-life of an isomeric state
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| 5. |
- Palacz, M, et al.
(författare)
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In-beam gamma-ray spectroscopy of Cd-103
- 1997
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Ingår i: NUCLEAR PHYSICS A. - : ELSEVIER SCIENCE BV. - 0375-9474. ; 624:2, s. 210-224
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Excited states of Cd-103 were studied in the reaction Ni-58(Cr-50,4pn)Cd-103. The NORDBALL array with neutron and charged particle detectors was employed for the detection of gamma rays and light evaporated particles. The level scheme of Cd-103 was signif
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| 6. |
- Palacz, M, et al.
(författare)
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In beam gamma-ray spectroscopy of very neutron deficient odd-cadmium isotopes
- 1997
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Ingår i: Acta Physica Polonica B. - : ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS. - 0587-4254 .- 1509-5770. ; 28:1-2, s. 309-313
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in the very neutron deficient odd cadmium isotopes Cd-99, Cd-101 and Cd-103 are discussed in terms of the nuclear shell model. Systematics of excited states in Cd99-109 is presented.
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| 7. |
- Sohler, D, et al.
(författare)
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Maximally aligned states in Ag-99
- 2003
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 16:2, s. 171-175
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Tidskriftsartikel (refereegranskat)abstract
- Excited states of Ag-99 were populated via the Cr-50 + Ni-58 (261 MeV) reaction using the NORDBALL detector array equipped with charged-particle and neutron. detector systems for reaction channel separation. On the basis of the measured gammagamma-coincidence relations and angular distribution ratios a significantly extended level scheme has been constructed up to E-x similar to 7.8 MeV and I = 35/2. The experimental results were described within the framework of the shell model. Candidates for states fully aligned in the pig(9/2)(-3)nu(d(5/2),g(7/2))(2) valence configuration space were found at 4109 and 6265 keV.
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| 8. |
- Cederkall, J, et al.
(författare)
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Maximum spin aligned states in Ag-98(47)51
- 1998
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Ingår i: EUROPEAN PHYSICAL JOURNAL A. - : SPRINGER VERLAG. - 1434-6001. ; 1:1, s. 7-9
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- New excited states have been observed in the neutron deficient isotope Ag-98 following the Ni-58+Cr-50-->Te-108* heavy-ion reaction. One of these states may be interpreted as a maximum spin aligned state of the pi g(9/2)(-3) nu vg(7/2) configuration. Othe
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| 9. |
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| 10. |
- Palacz, M, et al.
(författare)
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In-beam gamma-ray spectroscopy of Cd-101
- 1996
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Ingår i: NUCLEAR PHYSICS A. - : ELSEVIER SCIENCE BV. - 0375-9474. ; 608:2, s. 227-242
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Excited states of Cd-101 were studied in the reaction Ni-58(Cr-50,2p alpha n)Cd-101. The NORDBALL array with a Neutron Wall and a Silicon Ball was employed for the detection of gamma-rays and evaporated particles, The level scheme of Cd-101 was significan
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